The Geng Lu Bu, also called the Manual of Sea Routes, was compiled in ancient times by fishermen and was a treasured navigational aid. Geng was an ancient unit of distance measurement equal to 30 kilometers. Lu refers to fishing routes, while Bu means books. For thousands of years, the fishermen of Hainan endured the heat of the scorching sun and braved the stormy seas, mapping submerged and treacherous ocean currents in order to find the routes across the vast, unmarked surface of the roiling sea.
Once, Hainan fishermen depended on the Manual of Sea Routes to guide them as they braved the strong northern winds on their journeys south to gather the gifts of the sea. These days, the manual has been replaced by modern sat-nav systems. Although it's not in use as a navigational tool any longer, the manual is still quite valuable for many other reasons and is accorded the great honor it is due.
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